Airtight cover

ABSTRACT

An airtight cover aims to cover an opening edge of a container and includes an upper rigid lid and an airtight flexible plate located below the upper rigid lid. The airtight flexible plate includes a sealing rim in contact with the opening edge and a central portion and a peripheral portion located respectively on an inner side and an outer side of the sealing rim. The sealing rim and upper rigid lid are interposed by a gap. When the airtight flexible plate contacts with the opening edge through the sealing rim to make the central portion continuously move downward, the peripheral portion is forced to warp upward, and the upper rigid lid presses the peripheral portion to bend downward. Hence the contact area between the sealing rim and opening edge increases, which can securely seal the container to meet requirements of usage.

FIELD OF THE INVENTION

The present invention relates to an airtight cover and particularly to an airtight structure for the airtight cover,

BACKGROUND OF THE INVENTION

Please referring to FIGS. 1 and 2 for a conventional airtight cover 1 which is made of pliable material and formed in a plate shape to be used on a container 2 with an opening smaller than the airtight cover 1. When in use, the airtight cover 1 is laid over and adsorbed on an opening 3 of the container 2 by applying a pressure on the center of the airtight cover 1. Then the opening 3 is sealed to isolate the container 2 from the external air, therefore can prevent foods or drinking water held in the container 2 from being contaminated.

The aforesaid conventional airtight cover 1 is simple in operation and adaptable to containers 2 in different sizes, hence is widely used as a temporary lid. However, when the airtight cover 1 is used to seal the container 2, due to its center is pressed to sink slightly into the container 2, the rim of the airtight cover I Warps upward. This makes the contact area between the airtight cover 1 and opening 3 become smaller. As a result, the air isolation effect becomes worse and a small gap is easily generated. Moreover, the upward warping rim of the airtight cover 1 causes users inconveniences when in use. For instance, users could incidentally hit the airtight cover 1 when they move the container 2 and result in loosening and dropping of the airtight cover 1 to lose the air isolation effect thereof.

SUMMARY OF THE INVENTION

Therefore the primary object of the present invention is to provide an airtight cover that is adaptable to various types of containers and provides satisfactory airtight effect to meet requirements of usage.

Another object of the present invention is to provide an airtight cover that is adaptable to various types of containers and provides function of vacuum pumping for preservation.

The airtight cover of the invention aims to cover an opening edge of a container and includes an airtight flexible plate and an upper rigid lid. The airtight flexible plate is located below the upper rigid lid and includes a sealing rim in contact with the opening edge and a central portion and a peripheral portion that are located respectively on an inner side and an outer side of the sealing rim. The upper rigid lid includes an installation hole, and the airtight flexible plate includes an air vent which corresponds to the installation hole and holds a check valve. The upper rigid lid and a distal end of the upper rigid lid are interposed by a gap.

By means of the structure mentioned above, when the airtight flexible plate contacts with the opening edge through the sealing rim to make the central portion sink continuously downward, the peripheral portion is forced to warp upward. Meanwhile, the upper rigid lid compresses the peripheral portion and sealing rim downward to increase the contact area between the sealing rim and opening edge, so as to form secure sealing of the container. In addition, after the check valve has been installed on the upper rigid lid the interior of the container can be vacuumed via an air extraction duct. When vacuum is formed inside the container, a pressure difference between an inside and an outside of the container is formed, therefore the airtight flexible plate and the upper rigid lid are pressed downward by the atmospheric pressure. Hence the peripheral portion is securely pressed downward and the central portion sinks severely downwards to further increase the contact area between the sealing rim and the opening edge, thus the vacuum airtight effect of the container can be maintained longer to preserve the goods and meet requirements of usage.

The foregoing, as well as additional objects, features and advantages of the invention will be more readily apparent from the following detailed description, which proceeds with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic view of a conventional airtight cover.

FIG. 2 is a schematic view of a conventional airtight cover in a use condition.

FIG. 3 is a perspective view of the invention.

FIG. 4 is a cross section of the invention.

FIG. 5A is a first schematic view of the invention in a use condition.

FIG. 5B is a second schematic view of the invention in another use condition.

FIGS. 6A through 6D are schematic views of containers adaptable to the invention.

FIG. 7 is a schematic view of the invention in a vacuuming condition.

FIG. 8 is a schematic view of the invention in a de-vacuuming condition.

FIG. 9 is a partial schematic view of the invention after being vacuumed to show an airtight condition.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Please referring to FIGS. 3, 4 and 5A, the present invention aims to provide an airtight cover to cover an opening edge 11 of a container 10. The airtight cover comprises an airtight flexible plate 20 and an upper rigid lid 30. The airtight flexible plate 20 includes a sealing rim 21 in contact with the opening edge 11 and a central portion 22 and a peripheral portion 23 that are located respectively on an inner side and an outer side of the sealing rim 21. The upper rigid lid 30 is located above the airtight flexible plate 20, and the upper rigid lid 30 and a distal end of the upper rigid lid are interposed by a gap D.

The upper rigid lid 30 also includes an annular grasp portion 31 which is extended upward from the upper rigid lid and includes an installation hole 32 formed therein. The airtight flexible plate 20 includes an annular flange 24 corresponding to and latched on the installation hole 32 to allow the airtight flexible plate 20 and upper rigid lid 30 to couple together.

The airtight flexible plate 20 further includes a groove 25 formed on the peripheral portion 23 and an inverse flange 26 extended from the groove 25, and the upper rigid lid 30 includes a flange 33. The flange 33 can be held in the groove 25 and encased by the inverse flange 26 so that the upper rigid lid 30 and airtight flexible plate 20 can be in contact with each other closely and smoothly to press the peripheral portion 23 downward.

The airtight flexible plate 20 further includes an air vent 27 formed in the annular flange 24 to hold a check valve 40 for an unidirectional evacuation. The check valve 40 is made of flexible material and gradually shrunk to form a duck-beak end 41 with a crevice 42 formed therein. When the check valve 40 forms a positive pressure inside, the check valve 40 is pushed to open the crevice 42 and discharge air. When the positive pressure is absent, the duck-beak end 41 generates naturally a compression force due to its geometric shapes to close the crevice 42 to form an airtight structure.

Also referring to FIGS. 5A and 5B for schematic views when the airtight cover of the invention is in use. First, make the airtight flexible plate 20 contact with the opening edge 11 through the sealing rim 21 (as shown in FIG. 5A), and make the central portion 22 sink downward to force the peripheral portion 23 to wrap upward. Meanwhile, the upper rigid lid 30 compresses the peripheral portion 23 downward (as shown in FIG. 5B); as a result, the contact area between the sealing rim 21 and opening edge 11 increases to form secure sealing of the container 10. Also refer to FIGS. 6A through 6D for various types of containers adaptable to the invention, such as 10A, 10B, 10C and 10D. The airtight flexible plate 20 can respectively contact and seal an opening edge 11A, 11B, 11C and 11D to provide a satisfactory airtight effect for the containers 10A, 10B, 10C and 10D.

Please referring to FIGS. 7, 8 and 9, after the airtight cover of the invention is mounted onto the container 10 and covered the opening edge 11, vacuuming can be performed through using an air extraction duct 50 to cover the check valve 40 (as shown in FIG. 7) to extract the air, thus the container 10 can form a vacuum condition to preserve goods or foods. To break the vacuum condition, the duck-beak end 41 needs to be squeeze (as shown in FIG. 8) to open the crevice 42, then air 60 can flow into the container 10 through the air vent 24. Referring to FIG. 9, when the airtight flexible plate 20 contacts with the container 10 initially, its position is shown in the broken line A; when the upper rigid lid 30 is pressed downward, the position of the airtight flexible plate 20 is changed as shown in another broken line B with increased contact area between the sealing rim 21 and opening edge 11. When the container 10 is vacuumed, due to the pressure difference between the inner side and the outer side of the container 10, the central portion 22 sinks continuously to further increase the contact area between the sealing rim 21 and opening edge 11, thus the airtight effect can be further enhanced.

As a conclusion, through the structure that the upper rigid lid compresses the airtight flexible plate downward, the contact area between the airtight flexible plate and opening edge increases, therefore the airtight effect can be enhanced. In addition, the invention can provide vacuuming effect through disposing the check valve. When the container is vacuumed inside, the pressure difference between the inner side and the outer side of the container is formed, and the airtight flexible plate and the upper rigid lid are pressed downward by the atmospheric pressure. Thus, the peripheral portion of the airtight flexible plate is further compressed to bend downward, and the central portion sinks more to further increase the contact area between the sealing rim and opening edge, thus can keep the container in a vacuumed airtight condition even longer to meet requirements of usage. 

What is claimed is:
 1. An airtight cover for covering an opening edge of a container, comprising: an airtight flexible plate including a sealing rim in contact with the opening edge and a central portion and a peripheral portion located respectively on an inner side and an outer side of the sealing rim; and an upper rigid lid which is located above the airtight flexible plate, and includes an annular grasp portion which is extended upward from the upper rigid lid and includes an installation hole, wherein the airtight flexible plate includes an annular flange corresponding to and latching on the installation hole, and wherein the sealing rim and a distal end of the upper rigid lid are interposed by a gap.
 2. The airtight cover of claim 1, wherein the airtight flexible plate includes a groove formed on the peripheral portion, and the upper rigid lid includes a flange corresponding to the groove.
 3. The airtight cover of claim 2, wherein the airtight flexible plate includes an inverse flange extended from the groove.
 4. The airtight cover of claim 1, wherein the airtight flexible plate includes an air vent formed in the annular flange to hold a check valve.
 5. The airtight cover of claim 4, wherein the check valve is gradually shrunk to form a duck-beak end with a crevice formed therein. 